The present invention relates to light fixtures and more particularly low voltage outdoor light fixtures that receive current through wires connected to an external power source.
Low voltage outdoor light fixtures are widely known. Such fixtures typically are used to illuminate gardens, outdoor walkways, driveways, patios and other areas or to spotlight sculptures, trees, structures and other objects. Typically, low voltage outdoor light fixtures are constructed of metal or plastic, and have a power source, a stake suitable for being inserted into the ground and for supporting the other components of the light fixture, a light bulb, and a globe that protects the light bulb, diffuses light emitted from the light bulb and provides decoration. In some fixtures, the power source includes solar panels that are used to generate electricity to power the light bulb. In other fixtures, a low voltage power supply provides typically about 12 volts AC through a wire that runs--e.g., underground--from the low voltage power supply to the light fixtures.
Generally, more than one fixture may be connected to a single low voltage power supply in the known type of power arrangement. In such cases, the wire carrying current from the power supply typically is laid underground such that it emerges from the ground to connect to a light fixture and then runs further underground until it emerges to connect to the next fixture and so forth until all of the desired light fixtures are wired to the power supply.
Various apparatus are known for connecting the wire running from the power supply to a light fixture. A commonly used connection scheme is a sliding connector, which is described in U.S. Pat. No. 4,774,648. The connector incorporates a stake that has a top with a hooked groove, which includes a pair of upwardly protruding L-shaped guides suitable for slidably receiving laterally protruding legs near the bottom of the assembly used for mounting the bulb and the globe (bulb/globe assembly). In such a scheme, the wire is looped over the top of the stake and nestles in the groove between upwardly extending guides, then the bulb/globe assembly--which has downwardly protruding pointed conductive prongs--is slid into place such that, when a connection is successfully made, the pointed conductive prongs pierce the wire's insulation and provide a conductive contact.
Other types of sliding connectors are also known. For example, another known sliding connector has hooked guides protruding either directly from the bulb/globe assembly or from a post extending from the bulb/globe assembly. The hooked guides are adapted to receive the top of the stake and the conducting prongs are situated between the hooked guides. In this scheme, the wire is looped through the hooked guides and then the top of the stake, or a retaining tab, is slid onto the bulb/lens assembly between the guides.
In another known scheme for connecting the wire to a fixture the wire terminates at the light fixture and a pair of contacts is crimped to the end of the wire. Such a crimped connector is discussed in U.S. Pat. No. 4,814,961.
Sliding connectors possess a number of known disadvantages. Difficulty in making a conductive connection is one such disadvantage. Often in installation of light fixtures using sliding connectors, the pointed conductive prongs do not adequately pierce the insulation of the wire, so a conductive contact is not made. The installer therefore must slide the connector components apart, re-align the wire and then slide the components back together. This process must be repeated until a conductive contact is made.
A further disadvantage of sliding connectors is that a longitudinal incision may be made in the wire's insulation as the contacts are slid into place. This incision is longer than necessary to make a conductive contact. A further related disadvantage is that each time the installer must repeat the sliding process--if multiple attempts to form a conductive contact are required--the damage to the insulation may be increased.
A still further disadvantage of sliding connectors is that a shearing force can be applied by the pointed conductive prongs.
Yet another disadvantage is that the wire insulation may be damaged by the incision, which increases the risks of short circuits, sparking and other known disadvantages inherent in exposed wiring.
Crimped connectors also possess a number of known disadvantages. One such disadvantage is that connections to multiple light fixtures cannot be achieved with one uninterrupted wire because the wire must be cut so the crimped connection can be made at the loose end.
A further disadvantage of crimped connectors is that installation is relatively complicated and time consuming.